That's fine to disagree, in most scenarios you're correct, calm and soft can diffuse a situation better. In the context I'm speaking of, it didn't, so loud, firm and brining out the accent is what did. Once people were on the back foot knowing they couldn't speak to you in a disgusting way or grab at you or scream in your face, you could then have a more pleasant interaction. For whatever reason, hearing certain voices had more of an effect at doing that than others did. That was just how it was, and to be honest it did set people at a disadvantage for the kind of places they were put to work, when all they wanted was a lovely, no problem, quieter place, not somewhere that appeared on Holidays from Hell!
This was something that was discussed by higher management based on years of feedback and observations, as was my main comment of which accents worked better with which demographic. It wasn't something they plucked from thin air, it was through decades of feedback, reports, sales figures and higher management observation. In fact, when Direct Holidays (Scottish based) and Panorama (Irish based) started to merge with Airtours and Aspro, and for a while, they were all still seen as separate entities. Direct Holidays requested Scottish reps where possible for their predominant properties and Panorama requested either Irish, Scottish or Northern as their client base was Irish. This is just what happened, whether right or wrong, that's just how it was because that's what worked. Accent bias and preconceptions exist, whether rightly or wrongly, and so when needed, you have to work that to your advantage.